The “GestIC®” integrated circuit, also known as MGC3130 manufactured by Applicant, is a highly sensitive capacitive sensing technology, its sensitivity revealing the problem addressed in this disclosure. Various application notes regarding GestIC®—Technology are available for download at Applicant's website, for example, application note “MGC3130—Sabrewing Single-Zone Evaluation Kit User's Guide”, published 2013 by Microchip Technology Inc. is hereby incorporated by reference.
Such an integrated circuit is coupled with various electrodes for generating an alternating electric field, for example using a 100 kHz square wave signal fed to a transmission electrode. A plurality of receiving electrodes are used to sense distortions in the generated electric field and process received signals to compute a three-dimensional location of an object, such as a finger or a hand entering the detection field.
The feeding lines between the integrated circuit and the electrodes may cause unwanted additional capacitive coupling in such a system. Other capacitive based sensing systems, such as one-dimensional (e.g. buttons) or two-dimensional (e.g. Touchpads) sensing systems may face similar problems.